The present invention relates to hydraulic antivibration mountings, in particular hydraulic antivibration mountings mounted between an engine and a motor vehicle structure.
More particularly, the invention relates to a hydraulic antivibration mounting comprising:
a rigid inner strength member extending longitudinally along an axis;
a rigid cage comprising a tubular wall and a flange, the tubular wall extending between two axial ends and surrounding the inner strength member, and the flange extending radially outwards front the tubular wall at one of its axial ends;
a cylindrical outer strength member extending likewise between two axial ends, the cage being received therein and the outer strength member having a shoulder and a collar at one of its axial ends, the shoulder co-operating with the flange and the tubular wall of the cage to define a narrow channel extending around a circular arc centered on the axis, and the collar extending from the shoulder perpendicularly to the axis;
an elastomer body connected to the inner strength member and to the cage, covering at least a fraction of the surface of the tubular wall and of the flange of the cage facing the outer strength member, said elastomer body being shaped to close the channel in leaktight manner and to co-operate with the outer strength member to form at least two pockets that communicate with each via the channel, the two pockets and the channel being filled with a damping liquid, and one of the pockets being deformable when the inner strength member and the cage are subjected to radial displacement relative to each other; and
a plate secured to at least one element selected from the cage and the outer strength member, the plate extending perpendicularly to the axis and including fixing means for fixing the mounting to a part external to the mounting.
As shown in FIG. 1, mountings of this type are already known in which the plate 17 rests on the flange 7 and encloses the cage 3 in the outer strength member 5, and in which the collar 22 extends radially towards the outside of the mounting, substantially on the same surface as the plate 17 and which is crimped to the edges of the plate 17.
Mountings are also known of the kind shown in FIG. 2 in which the outer strength member 5 has a collar 22 extending from the shoulder 21 towards the inner strength member 2 so as to enclose the cage 3 in the outer strength member 5, and in which the plate 17 is welded to the outside wall of the outer strength member 5.
Those mountings comprise two strength members, a cage, and a plate. The engagement in the outer strength member of the assembly constituted by the inner strength member, the cage, and the elastomer body, and the crimping or welding of the outer strength member to the plate need to be performed as two distinct successive operations.
Such mountings thus present the drawbacks of relatively high weight and manufacturing cost and of needing to be assembled in two operations, thereby requiring tooling that is relatively complex.
A particular object of the present invention is to mitigate those drawbacks.
To this end, according to the invention, in a mounting of the kind in question, the collar extends radially outwards from the shoulder and includes at least one surface portion facing the flange with a thickness of the elastomer body being interposed between the collar and the flange, the collar is fixed directly to the flange by crimping, and at least one of the elements selected from the collar and the flange constitutes the plate.
By means of these dispositions, the plate and the collar or the flange constitute a single piece only, thereby making it possible to reduce the number of parts in a mounting of the invention compared with prior art mountings, and thus to simplify manufacture thereof by reducing the number of assembly operations. Consequently, this makes it possible to reduce the manufacturing cost and the weight of this type of mounting.
In preferred embodiments of the invention, recourse may optionally also be had to one or more of the following dispositions:
one of the elements selected from the collar and the flange has at least one crimping orifice with a countersunk hole to form means for retaining a crimping bead formed out of the same material as the other one of said elements;
the plate is constituted by the flange and extends in a plane substantially perpendicular to the axis;
the outer strength member is made of a material selected from: aluminum; steel; and a plastics material;
the shoulder is made by stamping the outer strength member; and
the shoulder is made by molding the outer strength member.